1. Field of the Invention
The present invention relates generally to air filtration systems and more specifically to an ionic air filtration apparatus positioned within an enclosure, such as enclosed a pet litter boxe.
2. Description of the Related Art
Ionic air filtration devices are well known in the art. For example, free standing ionic air filtration devices can be used to remove airborne particulate matter in a room. These ionic air filtration devices utilize two electronically charged electrodes having opposite polarities to draw air over the two electrodes. As airborne particulate matter approaches the second electrode (oppositely charged from the first electrode) the particles are trapped by the second electrode. Such a freestanding device that can be advantageously employed to reduce the concentration of airborne particulate matter indoors.
There are certain instances, however, where a particular airborne particulate matter is generated by a particular source. In these instances the prior art freestanding ionic filtration device must be positioned near the source of particulate matter in order to be most effective at reducing the concentration of airborne particulate matter emanating from the source. This solution is imperfect. A large percentage of the particles avoid entrapment by the device and the particles wind up scattered by airflow around the room.
Pet litter boxes are one common source of airborne particles in households. Pet litter boxes include open and enclosed structures. Although a freestanding ionic filtration device can reduce the amount of airborne particles if properly positioned near a closed pet litter box, inevitably a large percentage of the airborne particles are carried on air currents away from the filtration device and are thereby distributed in the air throughout a room. Although enclosed pet litter boxes reduce the distribution of airborne particles compared to open litter boxes, nonetheless a significant amount of unhygienic and foul smelling airborne particles are released from the opening to the enclosure.
U.S. Pat. No. 6,312,507 to Taylor et al (xe2x80x9cTaylorxe2x80x9d) describes an electro-kinetic air refreshener-conditioner that is attached to either a pet shelter or litter box to reduce air borne particulate matter. In Taylor, the device is attached either to the lip of an open-faced litter box or over a vent on the top of an enclosed pet shelter. As shown in FIG. 2B of Taylor, when the device is attached on the top of the enclosed shelter it draws air from within the pet shelter enclosure, through the device where it removes particulate matter from this air, and then extrudes the exhaust out away from the interior of the enclosure.
No air filtration device can remove 100% of the airborne particulate matter from the air that passes through the device. Thus, to the extent that the Taylor device fails to remove airborne particulate matter, the airborne particulate matter from the interior of the enclosure is distributed into the room in which the enclosure is located. Given that the extruded air might contain contagions and other undesirable matter, the Taylor patent leaves room for improvement.
What is needed is an improved system for reducing the amount of airborne particles released from enclosures such as pet litter boxes and animal shelters.
An air filtration system according to the present invention includes an enclosure having an opening (variously described as an entrance) and having a floor and a top covering the floor. The top can be a dome, a four-sided structure with a flat roof or any of a variety of other geometric designs. The air filtration system also includes an air duct, which is preferably positioned on the underside of the cover within the enclosure. The air duct has an exhaust vent positioned in close proximity to the opening to the enclosure and an air intake at a position within the enclosure that is distant from the opening. Within the air duct are two electrodes. Two electrode arrays can be employed as an alternative to two individual electrodes. A first electrode array is positioned closer to the air intake relative to the second electrode array and the second array is closer to the exhaust vent relative to the first array.
A voltage regulator is electrically coupled to the first and second electrodes (or electrode arrays). The voltage regulator creates a voltage differential between the first and second electrode arrays. As a result of the voltage differential an air flow is generated that moves air from the first electrode array to the second electrode array. As air moves from the first electrode array it carries airborne particulate matter that is attracted to and trapped by the second electrode array. In a preferred embodiment an ultraviolet light source is included in the air duct to irradiate exhaust prior to its exiting the exhaust vent.
The exhaust vent is preferably positioned over the opening to the enclosure so that the exhaust flows down from the top of the opening to the floor. This air flow created by the exhaust acts as an air curtain barrier that at least partially prevents air from the inside of the enclosure from escaping to the outside. The intake continues to draw air into the air duct so that air that was expelled out of the exhaust vent is recirculated into the air duct to be purified by the air filtration system.
In a preferred embodiment the air filtration system is employed in a covered pet litter box. Advantageously, the system substantially prevents particulate matter and odors from escaping the litter box while simultaneously purifying and the air within the litter box.